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NAME

       GRANT - define access privileges


SYNOPSIS

       GRANT { { SELECT | INSERT | UPDATE | DELETE | RULE | REFERENCES | TRIGGER }
           [,...] | ALL [ PRIVILEGES ] }
           ON [ TABLE ] tablename [, ...]
           TO { username | GROUP groupname | PUBLIC } [, ...] [ WITH GRANT OPTION ]

       GRANT { { CREATE | TEMPORARY | TEMP } [,...] | ALL [ PRIVILEGES ] }
           ON DATABASE dbname [, ...]
           TO { username | GROUP groupname | PUBLIC } [, ...] [ WITH GRANT OPTION ]

       GRANT { EXECUTE | ALL [ PRIVILEGES ] }
           ON FUNCTION funcname ( [ [ argmode ] [ argname ] argtype [, ...] ] ) [, ...]
           TO { username | GROUP groupname | PUBLIC } [, ...] [ WITH GRANT OPTION ]

       GRANT { USAGE | ALL [ PRIVILEGES ] }
           ON LANGUAGE langname [, ...]
           TO { username | GROUP groupname | PUBLIC } [, ...] [ WITH GRANT OPTION ]

       GRANT { { CREATE | USAGE } [,...] | ALL [ PRIVILEGES ] }
           ON SCHEMA schemaname [, ...]
           TO { username | GROUP groupname | PUBLIC } [, ...] [ WITH GRANT OPTION ]

       GRANT { CREATE | ALL [ PRIVILEGES ] }
           ON TABLESPACE tablespacename [, ...]
           TO { username | GROUP groupname | PUBLIC } [, ...] [ WITH GRANT OPTION ]

       GRANT role [, ...]
           TO { username | GROUP groupname | PUBLIC } [, ...] [ WITH ADMIN OPTION ]


DESCRIPTION

       The GRANT command has two basic variants: one that grants privileges on
       a database object (table, view, sequence, database, function, procedur-
       al  language, schema, or tablespace), and one that grants membership in
       a role. These variants are similar in many ways, but they are different
       enough to be described separately.

       As  of  PostgreSQL 8.1, the concepts of users and groups have been uni-
       fied into a single kind of entity called a role.  It  is  therefore  no
       longer necessary to use the keyword GROUP to identify whether a grantee
       is a user or a group. GROUP is still allowed in the command, but it  is
       a noise word.

   GRANT ON DATABASE OBJECTS
       This  variant of the GRANT command gives specific privileges on a data-
       base object to one or more roles. These privileges are added  to  those
       already granted, if any.

       The  key word PUBLIC indicates that the privileges are to be granted to
       all roles, including those that may be created  later.  PUBLIC  may  be
       thought  of  as  an  implicitly  defined group that always includes all
       roles.  Any particular role will have the  sum  of  privileges  granted
       directly to it, privileges granted to any role it is presently a member
       of, and privileges granted to PUBLIC.

       If WITH GRANT OPTION is specified, the recipient of the  privilege  may
       in  turn grant it to others. Without a grant option, the recipient can-
       not do that. Grant options cannot be granted to PUBLIC.

       There is no need to grant privileges to the owner of an object (usually
       the  user that created it), as the owner has all privileges by default.
       (The owner could, however, choose to revoke some of his own  privileges
       for  safety.)   The right to drop an object, or to alter its definition
       in any way is not described by a grantable privilege; it is inherent in
       the  owner,  and cannot be granted or revoked. The owner implicitly has
       all grant options for the object, too.

       Depending on the type of object, the  initial  default  privileges  may
       include  granting  some privileges to PUBLIC.  The default is no public
       access for tables, schemas, and tablespaces; TEMP table creation privi-
       lege  for  databases; EXECUTE privilege for functions; and USAGE privi-
       lege for languages.  The object owner may of course revoke these privi-
       leges.  (For maximum security, issue the REVOKE in the same transaction
       that creates the object; then there is no window in which another  user
       may use the object.)

       The possible privileges are:

       SELECT Allows  SELECT  [select(l)] from any column of the specified ta-
              ble, view, or sequence. Also allows the use  of  COPY  [copy(l)]
              TO.  For  sequences,  this  privilege also allows the use of the
              currval function.

       INSERT Allows INSERT [insert(l)] of a new row into the specified table.
              Also allows COPY [copy(l)] FROM.

       UPDATE Allows  UPDATE [update(l)] of any column of the specified table.
              SELECT ... FOR UPDATE and SELECT ... FOR SHARE also require this
              privilege  (besides  the  SELECT privilege). For sequences, this
              privilege allows the use of the nextval and setval functions.

       DELETE Allows DELETE [delete(l)] of a row from the specified table.

       RULE   Allows the creation of a rule on the table/view. (See the CREATE
              RULE [create_rule(l)] statement.)

       REFERENCES
              To create a foreign key constraint, it is necessary to have this
              privilege on both the referencing and referenced tables.

       TRIGGER
              Allows the creation of a trigger on the  specified  table.  (See
              the CREATE TRIGGER [create_trigger(l)] statement.)

       CREATE For databases, allows new schemas to be created within the data-
              base.

              For schemas, allows new objects to be created within the schema.
              To  rename  an existing object, you must own the object and have
              this privilege for the containing schema.

              For tablespaces, allows tables and indexes to be created  within
              the tablespace, and allows databases to be created that have the
              tablespace as their default tablespace. (Note that revoking this
              privilege will not alter the placement of existing objects.)

       TEMPORARY

       TEMP   Allows  temporary tables to be created while using the database.

       EXECUTE
              Allows the use of the specified function  and  the  use  of  any
              operators  that  are implemented on top of the function. This is
              the only type of privilege  that  is  applicable  to  functions.
              (This syntax works for aggregate functions, as well.)

       USAGE  For  procedural  languages, allows the use of the specified lan-
              guage for the creation of functions in that  language.  This  is
              the only type of privilege that is applicable to procedural lan-
              guages.

              For schemas, allows access to objects contained in the specified
              schema  (assuming  that  the objects' own privilege requirements
              are also met). Essentially this allows  the  grantee  to  ``look
              up'' objects within the schema.

       ALL PRIVILEGES
              Grant  all  of the available privileges at once.  The PRIVILEGES
              key word is optional in PostgreSQL, though  it  is  required  by
              strict SQL.

       The  privileges  required by other commands are listed on the reference
       page of the respective command.

   GRANT ON ROLES
       This variant of the GRANT command grants membership in a role to one or
       more  other  roles. Membership in a role is significant because it con-
       veys the privileges granted to a role to each of its members.

       If WITH ADMIN OPTION is specified, the member may in turn grant member-
       ship  in the role to others, and revoke membership in the role as well.
       Without the admin option, ordinary users cannot do that. However, data-
       base  superusers  can grant or revoke membership in any role to anyone.
       Roles having CREATEROLE privilege can grant or revoke membership in any
       role that is not a superuser.


NOTES

       The REVOKE [revoke(l)] command is used to revoke access privileges.

       When  a  non-owner  of  an  object  attempts to GRANT privileges on the
       object, the command will fail outright if the user  has  no  privileges
       whatsoever  on  the object. As long as some privilege is available, the
       command will proceed, but it will grant only those privileges for which
       the user has grant options. The GRANT ALL PRIVILEGES forms will issue a
       warning message if no grant options are held,  while  the  other  forms
       will issue a warning if grant options for any of the privileges specif-
       ically named in the command are not held.  (In principle  these  state-
       ments  apply to the object owner as well, but since the owner is always
       treated as holding all grant options, the cases can never occur.)

       It should be noted that database  superusers  can  access  all  objects
       regardless  of  object  privilege  settings.  This is comparable to the
       rights of root in a Unix system.  As with root, it's unwise to  operate
       as a superuser except when absolutely necessary.

       If  a superuser chooses to issue a GRANT or REVOKE command, the command
       is performed as though it were issued by  the  owner  of  the  affected
       object.  In  particular,  privileges  granted  via  such a command will
       appear to have been granted by the object owner.  (For role membership,
       the  membership  appears  to  have  been granted by the containing role
       itself.)

       GRANT and REVOKE can also be done by a role that is not  the  owner  of
       the  affected object, but is a member of the role that owns the object,
       or is a member of a role that holds privileges WITH GRANT OPTION on the
       object.  In  this  case  the privileges will be recorded as having been
       granted by the role that actually owns the object or holds  the  privi-
       leges  WITH GRANT OPTION. For example, if table t1 is owned by role g1,
       of which role u1 is a member, then u1 can grant privileges on t1 to u2,
       but  those  privileges will appear to have been granted directly by g1.
       Any other member of role g1 could revoke them later.

       If the role executing GRANT holds the  required  privileges  indirectly
       via  more  than  one role membership path, it is unspecified which con-
       taining role will be recorded as having done the grant. In  such  cases
       it  is  best  practice  to use SET ROLE to become the specific role you
       want to do the GRANT as.

       Currently, PostgreSQL does not support granting or revoking  privileges
       for  individual columns of a table.  One possible workaround is to cre-
       ate a view having just the desired columns and then grant privileges to
       that view.

       Use  psql(1)'s  \z  command to obtain information about existing privi-
       leges, for example:

       => \z mytable

                               Access privileges for database "lusitania"
        Schema |  Name   | Type  |                     Access privileges
       --------+---------+-------+------------------------------------------------------------
        public | mytable | table | {miriam=arwdRxt/miriam,=r/miriam,"group todos=arw/miriam"}
       (1 row)

       The entries shown by \z are interpreted thus:

                     =xxxx -- privileges granted to PUBLIC
                uname=xxxx -- privileges granted to a user
          group gname=xxxx -- privileges granted to a group

                         r -- SELECT ("read")
                         w -- UPDATE ("write")
                         a -- INSERT ("append")
                         d -- DELETE
                         R -- RULE
                         x -- REFERENCES
                         t -- TRIGGER
                         X -- EXECUTE
                         U -- USAGE
                         C -- CREATE
                         T -- TEMPORARY
                   arwdRxt -- ALL PRIVILEGES (for tables)
                         * -- grant option for preceding privilege

                     /yyyy -- user who granted this privilege

       The above example display would be seen by user miriam  after  creating
       table mytable and doing

       GRANT SELECT ON mytable TO PUBLIC;
       GRANT SELECT, UPDATE, INSERT ON mytable TO GROUP todos;

       If  the  ``Access  privileges''  column is empty for a given object, it
       means the object has default privileges (that is, its privileges column
       is  null).  Default  privileges  always  include all privileges for the
       owner, and may include some privileges  for  PUBLIC  depending  on  the
       object type, as explained above. The first GRANT or REVOKE on an object
       will  instantiate  the  default  privileges  (producing,  for  example,
       {miriam=arwdRxt/miriam})   and  then  modify  them  per  the  specified
       request.

       Notice that the owner's implicit grant options are not  marked  in  the
       access privileges display. A * will appear only when grant options have
       been explicitly granted to someone.


EXAMPLES

       Grant insert privilege to all users on table films:

       GRANT INSERT ON films TO PUBLIC;

       Grant all available privileges to user manuel on view kinds:

       GRANT ALL PRIVILEGES ON kinds TO manuel;

       Note that while the above will indeed grant all privileges if  executed
       by  a superuser or the owner of kinds, when executed by someone else it
       will only grant those permissions for which the someone else has  grant
       options.

       Grant membership in role admins to user joe:

       GRANT admins TO joe;


COMPATIBILITY

       According  to  the  SQL standard, the PRIVILEGES key word in ALL PRIVI-
       LEGES is required. The SQL standard does not support setting the privi-
       leges on more than one object per command.

       PostgreSQL  allows  an  object  owner to revoke his own ordinary privi-
       leges: for example, a table owner can make the table read-only to  him-
       self by revoking his own INSERT, UPDATE, and DELETE privileges. This is
       not possible according to the SQL standard. The reason  is  that  Post-
       greSQL  treats  the  owner's  privileges  as having been granted by the
       owner to himself; therefore he can revoke them too. In  the  SQL  stan-
       dard,  the  owner's privileges are granted by an assumed entity ``_SYS-
       TEM''. Not being ``_SYSTEM'', the owner cannot revoke these rights.

       The SQL standard  allows  setting  privileges  for  individual  columns
       within a table:

       GRANT privileges
           ON table [ ( column [, ...] ) ] [, ...]
           TO { PUBLIC | username [, ...] } [ WITH GRANT OPTION ]

       The  SQL  standard  provides  for  a  USAGE privilege on other kinds of
       objects: character sets, collations, translations, domains.

       The RULE privilege, and privileges on databases, tablespaces,  schemas,
       languages, and sequences are PostgreSQL extensions.


SEE ALSO

       REVOKE [revoke(l)]

SQL - Language Statements         2005-11-05                           GRANT()

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